ABSTRACT Pathological hoarding behaviors represent a massive public health burden. Approximately 3-5% of the population is estimated to have hoarding disorder, which is characterized by difficulties discarding, severe clutter, and excessive acquiring. These symptoms can range on a spectrum from normative and benign collecting, to extremely debilitating symptoms that rival the impairment noted in other severe and persistently ill psychiatric populations (e.g., schizophrenia). The course of hoarding is chronic and, if left untreated, symptoms can have serious and even life threatening ramifications for the patient and their larger community. Despite remarkable advances in understanding the phenomenology of hoarding, vulnerability or maintaining factors are still poorly understood, and hoarding is also considered difficult to treat, with only modest treatment gains noted for existing interventions. Gaining better insight into the phenomenology of hoarding is critical to identifying effective treatment targets. Decision making deficits have been widely proposed as a central psychopathological feature of hoarding based on clinical reports and preliminary neuroimaging data. A definitive gap in the extant research is that neuropsychological studies of decision making in hoarding have produced strikingly mixed results. We suggest that a potential explanation for these varied results is that decision-making impairments in HD may largely be specific to emotion-based decision making, and these studies have failed to account for the influence of emotional processes on decision paradigms. The primary aim of this study is to examine the role of emotion-based decision making in individuals who hoard. We seek to characterize these impairments by examining decision-making impairments across two measures derived within behavioral neuroeconomics, including one task that will examine value-based decision making under highly relevant domains of risk and ambiguity, as well as one task that captures multi-attribute decision making. In both tasks, an emotionally neutral condition will be compared to a stressful condition, allowing us to examine the emotion-cognition interaction in hoarding. To examine whether decision-making impairments are specific to those who hoard, a hoarding sample will be compared with age-matched individuals with anxious distress and healthy controls. Our secondary aims are to explore potential mechanisms of these decision making impairments, examining candidate moderators including peripheral physiologic response and subjective distress tolerance. The approach is innovative, because it represents an integration of psychology, neuroscience, and behavioral economics to create a more nuanced understanding of HD-related deficits. The proposed research is significant because it has the potential to explain a great deal of the overt symptoms of HD and functional impairments, and will directly inform future translational studies of novel treatment approaches (e.g., cognitive remediation, innovative technology) in hoarding and related conditions.